Arc-lamp electrode.



"UNITED STATES PATENT OFFICE.'

RICHARD FLEMING, OF LYNN,MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.`

.ARC-LAMP ELECTRODE.

Specification of Letters Patent.

Patented Oct. 29, 1907.

Application filed March 26, 1903. -Serial No. 149,670.

To all whom it may concern: Be it known that I, RICHARD FLEMING, a citizen of the United States, residingat Lynn, in the county-'of Essex, State-of Massachusetts, have invented lcertain new and useful Improvements in Arc-Lamp Electrodos, of which the following is a specification.

The object of my present invention is the construction o an' electrode which will give a luminous are of high eiliciency and which at the same timepossesses-good mechanical features. This object l attain by .theuse of a comparatively thin iron tube orshell into which a mass oflmagnetic oXid of iron, Fe3O4. is placed filling thetube or shell for a considerableportion of its length. Asthe magnetite'in the condition in which it is ordinarily putin the tube is a p'oorconductor of electricity, it is necessary to make the arc-end of the' electrode conf ducting in order vthat'the arc may be readily started.

This may be done by fusing over the end of the electrede, `whereupon the fused mass formed at the end of the electrode becomes sufficiently' conducting to allow of the arc being'readilystarted.'

ln operation, the metallic iron of which the tube'lis made and the magnetite fuse together at the arc end of the electrode, the metallic iron'being converted intooxids of iron, the most of .it .being converted into magnetite. Vaporizat'ien slowlytakes place from this fused mass giving a highly luminous arc. Instead'of employing magnetite alone as .the material with which 'thetube vorshellis filled, other'materials may easily be mixed With the magnet-ite by means of Whi ch the character of the light produced may be altered in various Waysas it is apparent that this form of elec- 'trede is peculiarly adapted for such changes of compositionz For a better understanding of my invention, refer ence may be had to.- the accompanying drawings in which I haye illustra-ted` one embodiment of my l"invention.

Of the drawings, Figure l represents an'elevation of 4acompletcd electrode made in accordance with my in- 'vention, Fig. 2 is a sectional elevation showing the construction of my electrode prior tothe time at which the'arc end is fused over, and Fig. 3 shows the appear; ance of the arc end of the electrode after fusion.

Referring to the drawings, l-represents an iron tube, and 2 represents a filling therefor of magnetic oxid of iron (Fe304) or magnetic oxid of iron mixedwith other L .materials in a granular form. The granular material is packed tightly in the tube. A piece of metal 3 such asa tack may be inserted in the granular material at the are end of the electrode to assist in starting and direct- `ing the fusing arc. The opposite end of the .tube may be llediwith a plug -i of some suitable material which retains the granular material in the tube. i After fusing over, the arci en'd oi the 'electrode assumes the somewhat irregular outline 1nd1cated at 5. The powdered ma,- terial filling the tube is a .poor conductor under normalr conditions and in operation the current is carried to the arc end of thev electrode from the terminal-clamp by the metal tube'. The mass -fornied at the arc end of the electrodevby fusion is conducting even when cold, howevenso that the arc may be readily started.

therefor composed principally of powdered oxd of, iron. one end of said` tube and its tilling being' fused together to form a 'conducting'. mass.

5. An electrode .composed 'essentially vor :1 metal and :i refractory oxid of the metail. tlic metallic cxid being' '.such :is to give. 1 liuninous'or flaming arc in consuming'.

In Witness lwhereof. l liave hereunto vset my linml this 23rd any or Mnl-eil, loos. l l

niouAnn ivtinuno:

Witnesses DVGALD ICK. MCKXLLoP. JOHN J. WALKER. 

